Method of flame spraying an alloy and the resulting article



Oct. 13, 1959 w e. GUTZEIT ETAL 2,908,539

METHOD OF FLAME SPRAYING AN ALLQY AND THE RESULTING ARTICLE Filed April 16. 1957 12 Phase Diagram 5 5 9 5 f /4o0 N FIG 1 t Eutectic Composition /300 39 9 y weight b P I12, 1200-- l i 5 //00 G g $0M Solid E I '1 Niclrel "if P Sol (Zion 50/. Eutectic 900- Primary Nic/re/ fared/c p- 800 I Primary N13 P Solution Eutectic Sol Eutectic 0 t orb/2M 2, Phosphorus 90 Nickel FIG 2 22 Base Metal Body lron, Copper,

Aluminum etc.)

Flame-Sprayed Coating. (Ni-P Alloy) YINVENTORSV Gregoire Gutzeit BY Joseph R. Spraul JMQQW M 3 W A ys.

mm Patent s n 1 2,908,589 METHOD OF FLAME SPRAYING AN ALLOY AND THE'RESULTING ARTICLE i r d rq Ga er Hi h and, nd s ph j p Munster-{Ind assignors toGen eral Arnerican Transportation Corporation, Chicag0,lll a corporation of NewYork r Application April 1 6, 1957, Serial No. 653,199 11 cl ims; Cl. 117-46 The present invention relates to processes of producing coherent coatings involving a nickel-phosphorus alloy.

It is a general object of the invention to provide a 2,908,589 raen q s 31 9.

. 2 'Crehan, the plating bath is Continuously or periodically regenerated by the addition of nickel cations and hypo phosphite ions, thereby to compensate'the same for'the depletion of these ions resulting from the plating re- 5 actions mentioned. Also, these plating reactions in the plating bath are productive of hydrogen ions, whereby hydroxyl ions are added in the regeneration tomaintain the desired pH of the plating bath. 1 4 While this method greatly extends the usefullife of the plating bath, it does not prevent the build-up;

phosphite anions and alkali metal salts therein assuming that the regeneration involves the addition of nickel s u1-' fate, sodium hypophosphite and sodium hydroxide); whereby ultimately it is necessary to discard the-used plating bath, as a result of the build-up of high concoating processif utilizing the .rnetallic reaction product ofa chemical plating bath of the nickel cation-hypophosphite anion typefand involving flame spraying of the product mentioned, whereby a coherent coating is produced that consists essentially of a nickel-phosphorus alloy.

Another object of the invention is to provide a process of producing a coherent coating upon a base metal body and involving aiflame spraying step, wherein the coating consists essentially of a nickel-phosphorus alloy. A further object of the invention is to provide an improved process of producing a coherent coating of the character noted, wherein the metallic reaction product of alchemical plating bath of thegnickel cation-hypophosphite anion type is'fed in finely divided form into a reduc flama ad byr ti d high velocity a es, so that theparticles of the reaction product are melted and the resulting melt is projected by the flame onto a surface to produce a coherent coating thereon, and wherein the reaction product and the coating have fundamentally different physical characteristics and. properties.

Further features'of the invention pertain to the par .ticular' composition of the nickel phosphorus"alloy. coatingand to the steps of the process of making the same;

whereby the fab'ove-outlined and additional operating featuresthereof are attained. I t s The invention, both am its organiza'tion and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawingiin whichz, A

' Figure 1 is a phase diagram 'of the nickel-phosphorus system, as far as it is pertinent to the nickel-phosphorus alloys that are produced in the coherent coatings, in accordance with "the present invention, and illustrating the mutual relationshipsjamongphase, temperatureand compositionof thesenickel-phosphorus alloys; and

centrationstherein of phosphite anions, sulfate anions and sodium cations, or alternatively tosubjectthe used plating bath to complete-chemical clean-up, as disclosed in the copendingapplication of Paul Talmey, Gregoire Gut'zeit and Donald E. Metheny, Serial No. 576,931, filed April 9, 1956. I f f' T Specifically, care must be exercised in, this connection to prevent precipitation of nickel phosphite in'the plating bath, since such precipitate serves as growth nuclei for the formation of metallic precipitate therein, with the resulting random decomposition of the plating bath. Specifically, the reactions involving the formation ofthe metallic precipitate in the plating bath are ,autocata'lytic; whereby the formation of any substantial metallic precipitate therein effects the totahdecomposition ofthe plating bath very, quicklyand throughout the, body'thereof entirely' at random and. altogether independentlyfo'f 'the catalytic surface of the body undergoing the plating operation. u Thus a chemical nickel plating bath becomess'pent whenv the phosphite anion concentration therein approaches the threshold of insolubility of nickel phosphite, and must be discarded, so as to prevent the possibility of random decomposition thereof in the plating system. The spent chemical nickel plating bath contains valu able nickel, hypophosphite and phosphite, as well' as sodium and sulfate; whereby it is ordinarily subjected to gross nickel salvage by treatment that induces decomposition thereof, the residue of the plating bath comprising an aqueous liquid having the previously-mentioned meani- Fig. 2 is a perspective view of a base metal block carry- 5 ing on one surface thereof a coherent flamej sprayed coating consisting essentially of a nickel-phosphorus alloyof the character noted. 7

Before proceeding with the description of the present invention, it isfirfst noted that injthe operation "of a continuous chemical nickel plating system of the character of ,tha't disclosed in US. Patent No; 2,658,839,

granted'jon November l0, 19 53, to Paul Talmey and William J; Crehan, there is employed a plating ba h of the nickel cation-hypophosplrite anion type; and in the plating operation nickel cations are reduced to metallic nickel and deposited. upon the catalytic surface I of the object undergoing the chemical nickel plating operation, andhypophosphite anions are correspondingly oxidized to phosphite anions andfa'ccumulate in the plating bath. lniaccordance the method of Talmey and lic precipitate suspended therein. The 'matter of the treatment of the spent chemical'nickel platingbath to induce decomposition thereof is exceedingly easy, as this phenomenon involvesthe previously-mentioned: re

actions that are autocatalytic; whereby the reactions, once initiated, rapidly spread throughout the plating bath and to the two ingredients (nickel cations and hypophosphite anions) .with the formation therein of the metallicpreproceed substantially on a quantitative basisjwith respect 'cipitate mentioned. Thus, all of the nickel cations in the plating bath are depleted in the presence of thenorrnal slight excess of hypophosphite anions; whereby the subsequent recovery of the metallic precipitate from the aqueous liquid effects the complete recovery of the nickel 0 cations from the residue of the spent chemical nickel plating bath. T he initiation of the reactions mentioned isalso' ,exceedingly simple as it is noted'that a chemical nickel plating bath is normally in a metastable state,

subject to catalyzed decomposition. Specifically, the

simplest procedure of initiating the reactions is to seed the spent chemical nickel plating bath with a small quantity of previously produced metallicprecipitate'prja small quantity of any catalytic material in finelyd'ivided form, such as .iron, cobalt, nickel, palladium, etc. Palladiumis highly catalytic and. may be employed even.

in the form of an aqueous solution of a salt thereof, such as the chloride, nitrate, etc. Also, the reaction rate in the spent chemical plating bath may be enhanced by appropriate increasing the pH thereof, by raising the temperature thereof to the boiling point, etc. Since the reactions are autocatalytic, as previously noted, it is very convenient, as a matter of manipulation, to initiate the same in a small quantity of the spent chemical nickel. plating bath contained in a beaker, or the like, and then return the. contents of the beaker into the vat or tank containing the bulk of the spent chemical nickel plating bath, thereby seeding the reactions in the bulk of the spent chemical nickel plating bath, in an obvious manner.

This metallic precipitate has been discovered to be an amorphous solid comprising a metastable supercooled solution of phosphorus in nickel, andhaving no specific composition, but normally containing as produced incident to the random decomposition of a chemical nickel plating'bath of the nickel cation-hypophosphite anion type, constituents comprising about 88 to 94% nickel and 6 to 12% phosphorus by weight. The phosphorus conent is affected by the pH and by the excess of both hypophosphite anions and phosphite anions in the spent chemical nickel plating bath, but only within the narrow range mentioned. Specifically, a high hypophosphite anion content, in the spent chemical nickel plating bath insures that incident'to random or induced decomposition thereof the metallic precipitate produced will have a high phosphorus content within the narrow range, .whereas a high phosphite anion content has only a slight eflfect in this regard. The metallic precipitate produced incident to the random decomposition of a pure simple freshly prepared standard aqueous solution of nickel sulfate and sodium hypophosphite always contains phosphorusin the range 6 to 12% by weight, frequently has a phosphorus content as high as 10% by weight, and occasionally has a phosphorus content as high as 12% by weight. This phenomenon is not really understood, as the random decomposition of the same standard solution in two separate batches is not necessarily productive of identical samples of metallic precipitate as to phosphorus content.

It has been discovered that this metallic precipitate has a melting temperature in the range 880" C. to 1100 C. depending upon composition; whereby the nickel and phosphorus constituents are in equilibrium.

These considerations will best be understood by reference to Figure 1 of the drawing, wherein there is illustrated a portion of the nickel-phosphorus system that is pertinent to the nickel phosphorus compositions produced by the melting of the precipitate noted. Specifically, it was discovered that the eutectic composition comprises nickel and phosphorus constituents containing about 89% nickel and 11% phosphorus by weight, and that the eutectic temperature is about 880 C. On the curve 11 the melting point of nickel (1453 C.) is indicated at 12 and the eutectic point is indicated at 13. Also, from the curve 11, it will be observed that a composition containing about phosphorus has a melting point of about 1150 C., a composition containing about 6% phosphorus has a melting point of about 1100 C., a composition containing about phosphorus has a melting point of about 950 C., and a composition containing about 12% phosphorushas a melting point of about 950" C. 7

' The eutectic composition of the system is not completely determined, since it appears that it involves fundamentally nickel and phosphorus, and since the proportions by weight are not in accordance with Daltons law; however, after heat-treatment above 400" C., only nickel and 'Ni P in the alloy have been detected by X-ray diffraction analysis.

' All of the compositions that are produced by melting of themetallic precipitate noted contain nickel and phosphorus in the previously-mentioned range by weight (about 8894% nickel and 642% phosphorus); and most of the compositions fall in the even more limited range containing about 90-93% nickel and 7-10% phosphorus by weight. Thus, it will be understood that when the metallic precipitate is heated to a temperature sulficiently high to melt the same, a melt is produced in which the nickel and phosphorus constituents are in equilibrium above the curve 11 of the phase diagram of Fig. 1. Upon subsequent cooling, the melt becomes supersaturated with nickel in the event the phosphorus content of the composition is below 11%; whereas upon subsequent cooling, the melt becomes supersaturated with Ni P in the event the phosphorus content of the composition is above 11%. Specifically, in the event there is a deficiency of phosphorus the melt becomes supersaturated with nickel, upon subsequent cooling; whereby solid nickel is formed in the eutectic solution as the composition of the solution moves downwardly and to.- ward the right along the curve- 11 and toward the eutectic point 13; hence,"when the cooling of'the melt proceeds to the eutectic temperature of about 880 C., considerable solid nickel is present in the solution of the eutectic composition, so that upon further cooling of the mass, this solid nickel is productive of primary nickel crystals in the mass of the eutectic composition that appear as substantial nickel dendrites in the eutectic matrix. Specifically, in the event there is an excess of phosphorus, the melt becomes supersaturated with Ni P, upon subsequent cooling; whereby solid Ni P is stormed in the eutectic solution as the composition of the solution moves downwardly and toward the left along the curve 11 and toward the eutectic point 13; hence, when the cooling of the melt proceeds to the eutectic temperature of about 880 C., considerable solid Ni P is present in the eutectic composition, sothat upon further cooling of the mass, this solid Ni P is productive of primary Ni P crystals in the mass of the eutectic composition that appear as small crystals ofNi P dispersed in the eutectic matrixf Accordingly, it is the melting of the metallic precipitate noted, followed by the subsequent cooling and solidifying of the melt, that is productive of the nickel-phosphorus alloy characterized by the eutectic composition vhaving dispersed therein the primary crystals mentioned. As previously noted, in this metallic precipitate, there is normally an excess of nickel .in the composition, whereby the nickel-phosphorus alloys produced is normally characterized by the dispersion therein of nickel dendrites. M

From a broad point of view, as a matter of definition, the original nickel-phosphorus material resulting directly from the nickel cation-hypophosphite anion reaction (the amorphous solid material described) may be termed an alloy, although it is not characterized by the eutectic composition noted; however, it is preferable to apply the term alloy to the final nickel-phosphorus material that results from the melting and subsequent solidifying of the original material mentioned, since this final material is characterized by the eutectic composition noted. Thus, hereinafter the term alloy will be used only to refer to this final material.

Now this nickel-phosphorus alloy is substantially different, as to characteristics and structure, from the solid nickel-phosphorus material that is chemically plated from a plating bath of the nickel cation-hypophosphite anion type and from the solid nickel phospho'rus material of the metallic precipitate. For examples: this nickel phosphorus alloy is substantially magnetic, whereas the nickel phosphorus plating and the metallic precipitate are substantially non-magnetic; and the specific resistance of this nickelephosphorus alloy is considerably less than that of the nickel-phosphorus plating vor the metallic precipitate. There are also many other physical and structural differences between this nickel-phosphorus alloy and the nickelphosphorus plating and the metallic precipitate that are not hQW discussed at length in the interest of brevity.

M oreover,it willbe understood that while the metallic precipitate must be melted to. effect the production of the nickel-phosphorus alloy described above, it is not necessary to maintain the condition of'the melt .for any particular timeintervalg i I It has also been discovered that the stray plating that may occur inan undesirable manner in a chemical nickel plating system of the character of that of the Talmey and Crehan patent is substantially 0151116 821111? compositionas that of the metallic precipitate previously described; whereby this stray plating that accumulates in the bottom of, fthe tanklin which'the chemical nickel plating bath, is stored, in the filters of the system, etc., may be accumulated and melted in the manner described above, either alone'or with themetallic'precipitate mentioned, in order to produce the nickel-phosphorus alloy described. Inf fa'chthe strayplating is also an amorphous solid comprising a metastable super cooled solution of phosphorusinnickel and having no specific composition, but normally containing, as produced, constituents comprising about 88to 94% nickelahd 6 'to 12% phosphorus by weight. Sincethe metallic precipitate mentioned and the stray plating mentioned are substantially identical, as amatterlof composition, they may be melted together in order to produce the unique nickel-phosphorus" alloy described. V

The salvage method described above is applicable to a wide variety of chemical nickel plating baths such, for example, as those disclosed in the following US. patents: No. 2,532,283, Brenner and Riddell; No. 2,658,841, Gutzeit and Krieg'; and No. 2,658,842, Gutzeit and Ramirez.

' A preferred chemical nickel platingbath of extremely wide utility is disclosedin the copending application of Gregoire Gutzeit, Paul Talmey and Warren G. Lee, Serial No. 569,815, filed March 6, 1956, nowPatent No. 2,822,294, granted on February 4, 195 8;:this plating bath essentially comprising an aqueous solution of a nickel salt, a hypophosphite, a complexing agent selected from the'gro'up consisting :of lactic acid and salts thereof, and an exalting additive selected from-the group consisting of propionic acid and salts thereof. In this plating bath, the absolute concentration of hypophosphite ions is within the range "0.15 to 1.20 mole/liter, the ratio between nickel ions and-hypophosphite ions is Within the range 0.25 to 1.60, the absolute concentration of lactic ions is within the range 0.25 toj0.0mole/liter, the absolute concentration of propionic ions-is Within the range 0.025

to 0.060 mole/liter, and the pH is :v'vithin the approximate range 4.0 to 5.6. 'This" particular chemical nickel plating bath-is most satisfactory in carrying outa wide variety of nickel plating; operations and of course, when 'itbecomes spent, it may be subjected to thesalv'ag'e method to produce thenick'el phosphorus alloy previously 4,

described; V

Inaccordance with the present method, the previously described reaction product (the metallic precipitate or the stray plating) is recovered from'a chemical plating bath oflthenickelcation-hypophosphite anion type, as previously described, and then subjected to suitable'treatment' to producea finely divided dry powder therefrom. Specifically the reaction product mentioned is first suitably dried andthen', if-"desiredrcrushed in a jaw crusher, followed byfurther reduction'in a roll grinder,- followed by still further reduction in a ball-rriill "The powdered p'r'oduct of the ball mill comprises a particle size in the general range 2O0to 325 mesh. 'Next the powdered product is treated with a suitable mineral acid in order to leach therefrom all traces of iron and other like impurities, a 5% sulfuric acid solution being adequate for this purpose. Theproduct is then suitablydriedand screened so that it'is suitablej for subsequentuse.

This-powder is then fed into'a reducing flame made by relatively high velocity gases, for instance, in accord- -ance 'with the Sch'oop process (see U.S. Patent No. 1,128,059 granted on February 9, 1915, to Max U.

The gun is directed so that the projected'melt impinges upona surface tobe coated; whereby it adheres thereto forming a coherent coating thereon. In the process, the finely divided particles ofthe amorphous sol id supercooled solution ,of phosphorus'in nickel are melted in the reducing flame, and the small glob ules'o fthe resulting melt areyhurled or projected onto the surface to 'becoated so that they accumulate andcohere, as well as adhere, thereon; whereby upon cooling and resolidification, the previously described nickel-phosphorus alloy is produced in theresulting coating. Thus it will be understood that-the finely; divided amorphous nickelphosphorus material that is fed into the flame-spray gun and the nickel-phosphorus all'oyfof thejjcoat'ingare fundamentally different from each other, both'as to structure and physical properties, as previously explained;

For example, the articleof manufacture 20 shown in Fig. 2 may be made in accordance with the abovedescribed process. Specifically, the article 20 comprises a base metal body 21 formed of-iron, copper aluminum, etc., and a flame sprayed'coherent coating 22 formed of the nickel-phosphorus'al-loy previously described.

The Schori'gunfModel Lf operated satisfactorily under the following Working conditions:

' The .Metcoigun Model E operated satisfactorily 'under the following working conditions:

The utilization df thesc' two flame-spray'gunsis in no way orit-ic'ah- 'as theyiwere employed entirely as a matter of 'conveniencefand dt will'be'unde'rstood'that an'y conventional-ilame-spr'aly' gun'may be employed. *lnthe operation of thetflam'e spray gun, a reducing'fiame should be maintained by' maintainin'g a slight 'cleficiencyoffoxygen to support completeco'mbustion of theinfianimable 'gas utilized, 'so as to minimize 'oxidation of 'the 'melted particles projected *by'the'fiame onto the surface undergoing the coating step; andwhile a'wide variety of combustion gases may be=employed,'propane isquite satisfactory for the present purpose. 4

.- Of course, itwill' be understood thatin accordance with the present'method, a wide variety of materials may be coated'including both metallic and non metallic bodies; and intact even'infiammable bodies formed of plastics, wood, etc., may becoated without burning thereof. However, as a practical matter, the coatings'are normally applied to base metal bodies for-medof iron, copper, aluminum and the usual' a'lloys thereofiand in the coating of such base metal bodies,'it is highly advantageous to 'prepare'the surface thereof prior to the'co'ating or Imetallizing 'step. Specifically, thesurface must be clean, free from grease, 'water'or other contamination. Moreover, the adhesion of the coating issubstantially' improved by preliminary grit blasting of the surface 1 .'The composite coherent coatingthus produced is normally -built-upir'1'layers, "each'having a thickness in the fgeneralrange 1 m2 inils; whereby the composite coating may have any desired ultimate thickness. Like other Schoop coatings, this coating is somewhat porous; however, the porosity of the coating may be decreased by using relatively small particle sizes in the powder that is fed to the flame-spray gun and by employing relatively higher velocities of the flame in the flame-spray gun.

-Mor eover, after the coating has been produced, the density thereof may be increased by flame polishing with a reducing flame. Furthermore, the general appearance of the coating may be substantially enhanced by wire bnushing, grit blasting, polishing, etc. While these coatings in excess of about 10 mils are relatively non-porous to aerated boiling water, the porosity thereof can be further reduced by impregnation with a suitable sealer, such as an organic lacquer Qrcoating agent of the vinyl, etc. type.

The nickel-phosphorus alloy of the coating is very advantageous in that it has a relatively low melting point, normally in the range 880 C. to 950 C., and the phosphorus content thereof acts as a de-oxidizing agent resulting in the capability of the molten droplets or globules to wet most metals even though they are coated with a thin normally unwetta-ble oxide film. For example, base metals containing substantially chromium (the usual stainless steels) are readily wetted by this alloy for this reason; whereby a coherent coating of the character described maybe readily flame-sprayed upon a base metal body containing substantial chromium; which coating is characterized by good adhesion, notwithstanding the usual unwettable oxide films carried by such stainless steels following careful cleaning thereof.

j Moreover, in order to minimize oxidation of the droplets or globules that are projected by the reducing flame, a suitable fluxing agent maybe advantageously incorporated in the powder that is fed into the flame-spray gun. Such fluxingcompounds as sodium borate may be employed in small amounts. 'By this arrangement, the normal oxide content of the alloy (usually about 10 to 15% by weight) in the coating may be reduced.

Also, it has been discovered that a ternary alloy of zinc, nickel and phosphorus may be produced in the manner described by feeding into the flame spray gun a mixture of finely divided metallic zinc and finely divided reactionproduct' of the character described. In the arrangement, about equal parts by weight of metallic zinc and reaction product are fed, in finely divided form, into the reducing flame;'whereby in' the coating thus produced there was a ternary alloy of zinc, nickel and phosphorus comprising constituents containing by-weight about 50% zinc, 44 to. 47% nickel and 3 to 6% phosphorus. Specifically, in the arrangement, a mil composite coating was provided upon a base metal body that comprised a 2.mi1s inner coating bonded to the base metal body and a 3 mils outer coating bonded to the inner coating, wherein the inner coating was formed of the ternary alloy noted and the outer coating was formed of the binary alloy noted. This composite coating offered very remarkable resistance to corrosion in a salt spray test, indicating a life of about 300 hours. t

. In view of the foregoing, it is apparent that there has been provided an improved process of producing a coherent nickel-phosphorus coating that may be carried out in a ready manner utilizing the conventional flame spray step of the Schoop method, as well as an improved corrosion-resistant coating comprising a nickel-phosphorus .alloy of the character described.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention. I.

What is claimed is: y

1. The process of producing a coherent coating,.which comprises providing finely divided particles of an amorphous solid supercooled solution .of phosphorus in nickel and containing about 88 to 94% nickel and 6 to 12% phosphorus by weight and characterized by alloying of the constituents thereof following melting and upon resolidification thereof, wherein said alloy is characterized by an eutectic matrix comprising nickel and phosphorus constituents containing about 89% nickel and 11% phosphorus by weight and having an eutectic temperature of about 880 C., feeding said particles into a reducing flame of relatively high velocity gases, whereby said particles are melted and the resulting melt is projected by said reducing flame, and directing said projected melt onto a surface so as to produce a coherent coating thereon and adhering thereto that consists essentially of said alloy.

2. The process set forth in claim 1, wherein said flame essentially comprises the combustion products of propane and oxygen. I

3. The process set forth in claim 1, wherein said particles essentially comprise the solid reaction product of a chemical plating bath of the nickel cationhypophosphite anion type. i

4. The process set forth in claim 1, wherein said particles essentially comprise the metallic precipitate that is formed incident to the decomposition of an aqueous solution containing nickel cations and hypophosphite anions.

5. The process set forth in claim 1, wherein said particles have a size in the general range --200 to 325 mesh.

6, The process of producing a coherent coating upon the surface of a base metal body, which comprises preparing the surface of said body by cleaning and roughening the same, providing finely divided particles of an amorphous solid supercooled solution of phosphorus in nickel and containing about 88 to 94% nickel and 6 to 12% phosphorus by weight and characterized by alloying of the constituents thereof following melting and upon resolidification thereof, wherein said alloy is characterized by an eutectic matrix comprising nickel and phosphorus constituents containing about 89% nickel and 11% phosphorus by weight and having an eutectic temperatureof about 880 (3., feeding said particles into a reducing flame of relatively high velocity gases, whereby said particles are melted and the resulting melt is projected by said reducing flame, and directing said projected melt onto the prepared surface of said body so as to produce a coherent coating thereon and adhering thereto that consists essentially of said alloy.

7. Theprocess set forth in claim 6, wherein said base metal contains sufficient chromium to interfere with .wetting thereof by molten nickel. V

8. The process of producing a coherent coating upon the surface of a base metal body, which comprises preparing the surface of said body by cleaning and roughening the same, providing finely divided particles of an amorphous solid supercooled solution of phosphorus in nickel and containing about 88 to 94% nickel and 6 to 12% phosphorus by weight and characterized by alloying of the constituents thereof following melting and upon resolidification thereof, .wherein said alloy is characteriz'ed by an eutectic matrix comprising nickel and phosphorus constituents containing about 89% nickel and 11% phosphorus by weight and having an eutectic temperature of about 880 C., feeding said particles into a reducing flame of relatively high velocity gases, whereby said particles are meltedand the resulting melt is projected by said reducing flame, directing said projected melt onto the prepared surface of said body so as to produce a layer thereon that consists essentially of said alloy, and then re-melting saidlayer by directing a flame of gases thereon so that upon resolidification of, said layer there is produced a coherent coating upon the surface of said body and adhering thereto. v

9. The process of producing a coherent coating upon the surface of a base'metal body, which comprises preparing the surface of said body by cleaning and roughening the same, providing finely divided particles of an amorphous solid supercooled solution of phosphorus in nickel and containing about 88 to 94% nickel and 6 to 12% phosphorus by weight and characterized by alloying of the constituents thereof following melting and upon resolidification thereof, wherein said alloy is characterized by an eutectic matrix comprising nickel and phosphorus constituents containing about 89% nickel and 11% phosphorus by weight and having an eutectic temperature of about 880 C., providing finely divided particles of a suitable solid refractory flux, feeding a mixture of said solution particles and said flux particles into a reducing flame of relatively high velocity gases, where by said solution particles and said flux particles are melted and the resulting melt is projected by said reducing flame, directing said projected melt onto the prepared surface of said body so as to produce a layer thereon that contains both said alloy and said flux, and then remelting said layer by directing a flame of gases thereon so that an underlayer of said alloy and an overlayer of said flux is produced thereon, whereby upon resolidification of said underlayer there is produced a coherent coating upon the surface of said body and adhering thereto.

10. The process of producing a coherent coating,

which comprises collecting the metallic reaction product from a chemical plating bath of the nickel cation-hypophosphite anion type, finely dividing said metallic reaction product to produce a particle size in the general range 200 to 325 mesh, washing said finely divided particles with an aqueous solution of a mineral acid to remove foreign impurity therefrom, drying said finely divided particles, feeding said dry finely divided particles into a reducing flame of relatively high velocity gases, whereby said particles are melted and the resulting melt is projected by said reducing flame, and directing said projected melt onto a surface so as to produce a coherent coating thereon and adhering thereto that consists essentially of a nickel-phosphorus alloy.

11. The process set forth in claim 6, wherein said base metal body is formed essentially of steel.

References Cited in the file of this patent UNITED STATES PATENTS 1,128,059 Schoop Feb. 9, 1915 2,633,631 Horvitz Apr. 7, 1953 2,762,723 Talmey et al Sept. 11, 1956 

1. THE PROCESS OF PRODUCING A COHERENT COATING, WHICH COMPRISES PROVIDING FINELY DIVIDED PARTICLES OF AN AMORPHOUS SOLID SUPERCOOLED SOLUTION OF PHOSPHORUS IN NICKEL AND CONTAINING ABOUT 88 TO 94% NICKEL AND 6 TO 12% PHOSPHORUS BY WEIGHT AND CHARACTERIZED BY ALLOYING OF THE CONSTITUENTS THEREOF FOLLOWING MELTING AND UPON RESOLIDIFICATION THEREOF, WHEREIN SAID ALLOY IS CHARACTERIZED BYAN EUTECTIC MATRIX COMPRISING NICKEL AND PHOSPHORUS CONSTITUENTS CONTAINING ABOUT 89% NICKEL AND 11% PHOSPHORUS BY WEIGHT AND HAVING AN EUTECTIC TEMPERATURE OF ABOUT 880*C., FEEDING SAID PARTICLES INTO A REDUCING FLAME OF RELATIVELY HIGH VELOCITY GASES, WHEREBY SAID PARTICLES ARE, MELTED AND THE RESULTING MELT IS PROJECTED BY SAID REDUCING FLAME, AND DIRECTING SAID PROJECTED MELT ONTO A SURFACE SO AS TO PRODUCE A COHERENT COATING THEREON AND ADHERING THERETO THAT CONSISTS ESSENTIALLY OF SAID ALLOY. 